I have a E36 with Max Speeding coilovers. Now I am ready to lower the rear end a bit, and while I realize this will affect camber, I'm wondering if it will also affect the toe in/out of the rear wheels? Wait for your help.

Yes, lowering the car will affect camber and also the toe in/out (In case of the rear wheels it should be toe-in).
An adjustment of camber and toe in/out after the lowering is recommended. Otherways it could end up in at least higher tire wear.

 

Yeah, lowering the ride height will increase camber, and add toe-in. The camber change is greater then the toe change. Wish you have a nice day.